Kagen Schaefer was holed up in his Denver apartment late one night in 2007 when the email popped into his inbox. It was from a famous filmmaker, a man known for making dark, psychological thrillers. He wanted Schaefer to create a masterpiece for him.

Schaefer, a 33-year-old Denver native who specializes in making puzzle boxes, was honored, if a little bit baffled. The craftsman wasn’t used to taking commissioned jobs; usually, when Schaefer designed a puzzle box—imagine a Rubik’s Cube that pops open on completion, revealing a secret compartment—he let careful calculation and the joy of creating riddles take the lead. His process had served him well: Over the past four years, he had won the grand prize, twice, at the prestigious Nob Yoshigahara Puzzle Design Competition, besting woodworkers who had been in the trade for decades. Despite being a relative novice in the field, he also took the revolutionary step of expanding the centuries-old craft into furniture. Collectors from Aspen to Russia were adding his pieces—which often cost thousands of dollars—to their art, furniture, and design collections.

The filmmaker, who insisted on anonymity for this article, told Schaefer that time wasn’t an issue. Neither was money. All he wanted was for Schaefer to design something that he was truly inspired by—a piece that captured his creative spirit. After a lengthy correspondence, the two settled on the project’s focus: It would be a desk that contained challenging puzzles that opened up secret drawers and compartments. It would also make music. It was a project that at first excited Schaefer but eventually became so complicated that it would consume him, sending him down the rabbit hole of despair. “I had no idea whatsoever,” says Schaefer, “what I was getting myself into.”

Ironton Studios and Galleries, a hulking metal building divided into studios for artists who work on canvas and sculpture, looks like most other converted warehouses in the River North Art District. Around the back, beyond a secret garden area overflowing with trees, shrubs, and vegetables, is Schaefer’s woodshop. The walls are stacked high with tools and puzzle prototypes; the floor is filled with enormous saws and drills. The studio is meticulously organized, and the sharp smell of sawdust fills the air.

Schaefer, a soft-spoken Jamie Oliver doppelgänger, has long been fascinated with puzzles. As a child, he would spend entire afternoons drawing elaborate mazes on huge sheets of paper. In first grade, a girl in his class brought in a puzzle box for show-and-tell. The young Schaefer was hooked when he realized that puzzles could be three-dimensional, not just two. He started designing his own rudimentary puzzle box prototypes in middle school, and loved the math and logic that went into the projects.

After earning a mathematics degree at Colorado College in 2000, Schaefer started working in the school’s math department as a teaching assistant. Still intrigued by puzzles, he also moonlighted as an assistant in the art department’s woodworking studio. He put those skills to immediate use by crafting the “Block Box,” a jewelry-box-size puzzle that requires the user to make more than 80 “moves” of the sliding tiles atop the box before it opens. The puzzle went on to win first place and the Puzzlers’ Award at the 2002 Nob Yoshigahara Puzzle Design Competition—a stunning victory for a newbie craftsman.

When he decided to get more serious about woodworking, Schaefer quit Colorado College and took a series of jobs in Los Angeles (furniture shop apprentice) and Denver (working in a wood production shop), before moving to Portland. There, he shared a studio space with a couple of reculsive woodworkers who made high-end customized furniture. After four years, Schaefer had mastered the type of woodworking skills he needed to make a living from puzzle boxes.

Schaefer returned to Denver in 2005 and shared a studio space in Highland, before moving to RiNo’s Ironton in 2008. His work was in high demand, thanks to wins at a few more international puzzle competitions and an article in Fine Woodworking magazine. Keeping up with his customers was difficult: Although the most basic puzzle boxes sell for an average of $400 to $500, they can require pricey materials, days of planning, and a minimum of a half-day of woodworking and assembly. More complicated projects can take months, even years, of work and sell for tens of thousands of dollars. Schaefer, though, earned a reputation as a collectors’ designer, as one of the few puzzle makers—often enigmas—who was easy to work with and willing to tackle unique projects. That’s why, when the filmmaker decided he wanted a puzzle desk, he called Schaefer.

The woodworker had built puzzle end tables and a coffee table before, but never something as complex as a desk. Designing the desk took him a year, as he struggled to find a balance between function (the filmmaker intended to work at the desk) and artistry (the craftsman ultimately included more than 20 interlocking puzzles). It was another year to track down the materials, including exotic woods from around the world, like South African pink ivory and Bastogne walnut. Schaefer took on the momentous task of carving every single screw—more than 200—out of lignum vitae, better known as ironwood. He also had to teach himself the not-insubstantial skill of designing instruments: Schaefer wanted hand-carved organ pipes to adorn the front of the desk. By pushing in on the drawers, you could make pitch-perfect music.

As he fell deeper into the project, Schaefer withdrew from the world. He spent months in the shop working and reworking prototypes of the desk’s interlocking puzzles, emerging only to eat. He stopped going out with friends for beers and bowling; he put his dating life on hold and ditched his hobby of swing dancing. Despite an effort to have a life outside of work, he became a recluse like his Portland studio mates. “This is the first project that slipped from me,” Schaefer says. After three years of struggling to complete the desk, an end came into sight. “I get possessive of the process,” he says. “There was this permanence to the project. It was unbelievably scary.”

This month, Schaefer plans to load the pieces of the six-foot-long puzzle desk into a van and drive it across the country to the filmmaker’s house in New York City, where he’ll assemble it on-site. He expects the delivery to be bittersweet: The desk required four years of his time, $10,000 of materials, and nearly his sanity. He had to buy new tools to fashion it and learn new skills to master the art of designing a musical instrument—one, no less, that was a functional piece of furniture. He charged the filmmaker the price of a “nice car” for the desk, but considering the time and expenses, it’s not clear whether Schaefer broke even on the project.

Today, Schaefer’s started working on projects for other clients, including a “Cafe Wall Table” (a credenza-type table with interlocking puzzles), and a series of “Lotus Tables” (circular tables with drawers that open up like flowers). His website (kagenschaefer.com) is loaded with a new inventory, and on First Fridays, his Ironton shop fills with art walkers trying out his puzzles and admiring the beautiful slabs of wood he stores for his projects. He’s created enough space between his work and his life that come evening, he can leave his projects on his bench and head out to bowl, dance, and socialize.

The filmmaker’s desk, though, is never far from his thoughts. When he starts a new project, or is mired in an old one, it bubbles up as inspiration and a warning. “Creating the desk was like having a strange dream at night,” Schaefer says. “And then I spent years trying to turn that dream into a tangible, functional, and beautiful reality.”

Eleanor Perry-Smith is a Denver-based freelance writer. Email her at letters@5280.com.